Abstract
Purpose :
The cold pressor test (CPT) induces a cardiovascular response, which may affect ocular blood flow and neuronal function. This study assessed whether optical coherence tomography angiography (OCT-A) can be used to evaluate CPT-induced ocular hemodynamic changes in healthy eyes and in eyes with primary open-angle glaucoma (POAG).
Methods :
Twenty-two healthy subjects and 23 subjects with POAG and a retinal fiber layer defect in only one hemifield underwent OCT-A imaging to evaluate CPT-induced vessel density (VD) changes in the peripapillary and macular areas. The CPT was performed by submerging a subject’s right hand in cold water (0–4°C) up to the wrist for 1 minute. Mann-Whitney U tests and Wilcoxon signed-rank tests were used to compare study groups and CPT-induced changes, respectively.
Results :
Baseline peripapillary and macular VD measurements were significantly lower in subjects with POAG than in healthy controls (all p < 0.05). Post-CPT VD measurements did not significantly differ from baseline in either healthy or glaucomatous eyes. Additionally , CPT-induced changes in VD did not differ between healthy hemifields in normal eyes and the corresponding undamaged and damaged hemifields in glaucomatous eyes (both p > 0.05). The VD changes also did not differ between damaged and undamaged hemifields in glaucomtous eyes (p > 0.05). Changes in VD were also not significantly influenced by a subject’s self-reported history of cold extremities.
Conclusions :
The CPT does not induce significant VD changes, as measured by OCT-A, in the peripapillary or macular areas of either healthy eyes or eyes with POAG. The VD, an all-or-nothing flow measure, may not be sensitive enough for evaluating cold-induced ocular hemodynamic changes.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.